feat: Implement new optional field to add a custom code to shortened url

[joaovitorzv]

i'll work on this if you like the feature you can merge.

[hyperloo]

How it will work? Can you explain to me, how you are thinking about it's integration with backend?

[joaovitorzv]

i've already made a pr in the backend handling this field, i'ts simple on frontend i just added the field and handle errors for this, on backend i see if user has passed any string to be his code, if yes i see on database if this code already exists if not the the link is generated with his code. if user just leave blank code is generated with shortId

[hyperloo]

Okay, that's fine then. Please make a PR to backend first with the proposed changes then I will merge this as well after a quick check. Will that be fine?

And don't forget to ⭐ the repo.